Optical instrument.



G. A. ROGERS.

OPTICAL INSTRUMENT.

APPLICATION FILED JULY 12, 1911.

Patented Aug. 19, 1913.

3' SHEETS-SHEET l.

G. A. ROGERS.

OPTICAL INSTRUMENT.

APPLIOATION FILED JULY 12, 191 1. v lfiygfigl n Patented Aug. 19, 1913.

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OPTICAL INSTRUMENT.

APPLICATION FILED JULY 12, 1911.

1 (O?@ 631 Patented Aug.19,1913.

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GEORGE ROGERS, OF CHICAGO, ILLINOIS.

OPTICAL INSTRUMENT.

Specification of Letters Patent.

Patented Aug. is, rare.

Application filed July 12, 1911. Serial No. 638,050.

To all whom itmay concern.

Be it known that I, GEORGE A. Rooms, a citizen of the United States, anda resident of Chicago, in the county of Cook and State of Illinois, haveinvented a new and useful Optical Instrument, of which the following isa specification.

My invention relates to improvements in optical instruments which areused for testing and treating the eyes, and has special reference to thevariety of instrument which depends upon the clearness with which thepatient sees under different adjustments, and which may be styledsubjective instruments. With such tests it is desirable to have the testobject at a considerable distance, and in order to make the tests at adistance it is now the uniform practice to place test cards at adistance of six meters, or approximately twenty feet, or as far away asthe conditions in the particular instance permit, and to place in asuitable frame before the eyes a series of spheres, cylinders andprisms, until the variety and amount of abnormality, if any, isascertained from noting through which the patient reports seeing best.

The objects of my invention are, first, the provision of such aninstrument in which distant objects may be employed as a target, and inwhich the size of the test object or angle of vision will not be changedfor different adjustments; second, the provision of such an instrumentin which the move ment or adjustment of a member thereof will suflice toproduce the requisite conditions and the use of the many test glasseswill be obviated; third, the provision in such an instrument offacilities whereby differ-'.

ent meridians of the same eye may be sub-. jected to differentsimultaneous tests; fourth, the provision in such an instrument offacilities for examining the binocular accommodation which a patient mayhave; and, fifth, the provision of an instrument which may be employedfor accelerating the muscular power or accommodation of the eye or eyes,and may also be used for the exercise or training of the muscles whichhave an effect on the vision.

I attain the above objects by the device illustrated in the accompanyingdrawings, in which Figure 1 is a plan of my invention arranged forbinocular examination; Fig.2 is a side elevation of the structure shownin Fig. 1; Fig. 8 is a rear elevation of the instrument, the base of thestand being broken off; Fig. 4 is a longitudinal section through a lenstube; Fig. 5 is a longitudinal section through the forward or objectivelens mounting; Fig. 6 is a transverse section through the forward lensmounting, showing the means for moving the lenses along the optical axisof the instrument; Fig. 7 is a transverse section through the forwardlens mounting, showing means for rotating said mounting about theoptical axis; and Figs. 8, 9 and 10 are diagrammatic views along theopticalaxis of the instrument showing adjustments for differentconditions.

Similar reference numerals refer to similar parts throughout the severalviews.

The instrument is supported upon a stand in the following manner topermit of leveling the same. The top of the stand is formed into a roundplate, 2, positioned vertically, against which is pivotally secured, bymeans of a bolt 3, the disk-shaped central portion 4 of a member, thelower end 5 of which projects downwardly into a vertical channel or slot6, provided on the stand. A recess 7, opening upon the slot 6, isprovided in the stand, and in this recess is a spring 8, upon whichrests a plunger 9, the outer end of which impinges against the lower end5 of the pivoted member. In the opposite wall of the slot, and oppositethe plunger 9, is a set screw 10, by means of which the verticalposition of the pivoted member may be adjusted. The upper end of thepivoted member terminates in a bracket 11, for holding a level 12. Atransverse channel 18 is provided through the plate 2, and entering thisfrom either side are the split arms 1.4:, the split portions of whichaccommodate the bolt 3 and the outer ends of which turn upwardly. Theupwardly turned portions of the arms Mare bored and threaded at 15 toreceive the right and left'threaded screw 16. This structure is foradjusting the instrument to the width of the eyes of the patient.

Upon the upwardly turned tops of the arms 14 fit sockets 17, which aresecured to lens tubes 18. The lens tube is clearly shown in Fig. 4. Therear portion thereof is flared and within the flared portion is secureda lens mounting 19. 'Back of the lens mounting the tube is closed-by aplate 20, which is set sufliciently back from the tube to form with thetube a lens cell 21, in which a test lens may be placed if occaopening22, from the edges of which extends backwardly an eye cup 23. In theforward portion of the lens tube is secured another lens mounting 24. I

Secured to the under portion of the lens tube near its forward end is anarm 25, the lower edge of which is provided with a rack 26.- The arms 25are longitudinally bored to telescopically receive the rods 27, shown inFigs. 1 and 2. A bracket 28 extends forwardly from the pivoted member 4and to this bracket is pivoted an arm 29; a carriage 30 slides upon thearm 29, and to the carriage 30 are secured the ends of the rods 27. Thearm 29 is graduated so that when the instrument is used for binoculareflects any desired amount of convergence of the systems may be securedwithin practical limits.

The carriage 30 has a standard 31 for supporting a test target, and whenthe instrument is employed in this manner both the accommodation fornearness of the object, and for convergence, is brought into play andthe character thereof may be determined. It is, of course, possible touse the instrument for one eye at a time, and when it is desired to doso the carriage 30 is detached from the rods 27 andthe arm 29 is swung.out of the way.

The forward or objective portion of the lens system is mounted in acarriage which travels upon the arm 25, and comprises a barrel 32 whichrotates upon its axis in straps 33, which extend about the arm 25 an dhold the barrel to the arm. Two longitudinal slots 34, at 90 from eachother, are provided in the barrel, and through these slots extend milledheaded pins 35 to operate lens mountings 36. By this arrangement theseparate lens mountings 36 may be moved independently longitudinally ofthe barrel 32. As shown in Figs. 2, 5 and 7, one of the straps 33 isprolonged below the arm 25 and in the prolonged portions is mounted anarbor 37, which is provided with a knurled head 38 and a gear 39 whichmeshes.

,,with the rack 26upon the bottom of the arm 25. By means of thisstructure the entire barrel may be racked backward and forward upon thearm 25. Asshown in Figs. 2 and 7, the straps 33 have brackets 40extending from one side thereof, in which is mounted an arbor 41 whichhas a knurled head 42 and .carries two gears 43, which'mesh with gears44 provided upon each end of the barrel 32, by'means of whichconstruction the entire barrel may be rotated upon'its axis within thestraps 33.

The above comprises the mechanical portions of my instrument whichpermit of the instrument being properly leveled-through theinstrumentality of the set screw 10;

which will permit of the separate lens tubes being adjusted. to thewidth of the patients eyes; which will also permit of the use of a neartarget and the convergence of the lens tubes for. reading andbinocular'tests and exercises; and which will permit of the rotation andeither separate or combined longitudinal movement of the members of the-mounting 19 in the rear of the lens tube.

In the lens mounting 19 is provided a negative spherical lens 46, ofexactly the same focal power and length as the lens 45. In the lensmountings 36, in the barrel 32, are

mounted two equal negative cylinders, 47

and 48, the combined focal power and length of focus of which shall beequal to that of the separate lenses 45 and 46. The cylinders 47 and48are disposed with their axes at right angles to one another, so theircombined action will be the same as that of a spherical lens.

The ptical action of the above arrangement can best be appreciated byreference to the diagrammatic Figs. 8, 9 and 10, in which the'forward orobjective portion of the system is represented as a single negativespherical lens for the purpose of simplicity.

In Fig. 8 the rays L are shown parallel, or as emanating from an objectat a considerable distance. The action of the objective lens OQL. issuch that a virtual image (designated V. L.) of the remote object isformed thereby at the distance of its focal length. In Fig. 8 theobjective lens is positioned one focal length forward of theintermediate lens. The objective and .intermediate lenses being of equalfocal length, this virtual image will be located two focal lengths fromthe positive lens 45, which is the anterior symmetrical point(designated A. S. P.) of that lens, or the distance at which the lenswill focus an image of an equal size the same distance upon its oppositeside or at the posterior symmetrical point (designated P. S. P.). Therear or eye lens 46 being interposed between the lens 45 and the imageformed thereby just, one focal length forward of the said image willrender the rays parallel or suitable for a normal or emmetropic eye.Hence a normal eye will see the distant object with this arrangement oflenses normally.

In Fig. 9 the objective lens is shown as racked forward of the anteriorprincipal focal plane (designated A. P.

F.) of. the intermediate lens. This will carry the virtual image forwardof the anterior symmetrical point of the intermediate lens. The resultthereof would be that a real image would be formed thereby anterior toits posterior symmetrical point, or at such a po sition that the eyelens 46 would no longer render the rays parallel. They would thereforeenter the eye, converging or suitable for a hypermetropic eye.

In Fig. 10 the objective lens is shown as racked back of the anteriorprincipal focus of the intermediate lens, which brings the virtual imagenearer than the anterior symmetrical point of the intermediate lens,which results in the formation of the image by the intermediate lensposterior to its osterior symmetrical point. Hence the action of the eyelens renders these rays divergent, which adapts them to a myopic eye.

The. amount or extent of convergence or divergence that is secureddepends upon the position of the objective lens anterior or posterior tothe anterior principal focus of the intermediate lens, and the change isequal for equal distances of movement. 1 have therefore provided a scale49 upon the arm 25, which is numbered to show the change in diopters fordifferent positions of the objective lens. By forming the objective lensof equal cylinders, the same principle is applied to different meridiansof an eye, where the eye under examination is astigmatic, and byrotating the objective element the meridians of greatest and leastrefraction may be determined and measured separately. I

Having described my invention, what I claim as new and desire to secureby Letters Patent is: v

1. In an optical instrument, a lens system comprising two negativeelements and an intermediate positive element, said elements being ofequal focal length, one negative and the positive element being locateda focal length apart and the remaining negative ele ment being movablealong the optical axis of the system.

2. In an optical instrument, a lens system comprising a negative and apositive spherical member of equal focal length positioned at a focallength distance from each other, and two equal negative cylindricalmembers having their axes at right angles, said cylindrical membersbeing movable relative to each other and relative to the sphericalmembers longitudinally of the optical axis of the system.

3. In an optical instrument, lens system comprising a negative and apositive spheriand two equal negative cylindrical members having theiraxes at right angles, said cylindrical members having a combined focallength equal to one of said spherical mem bers, and said cylindricalmembers being movable relative to each other and relative to thespherical members longitudinally of the optical axis of the system.

4:. In an optical instrument, a lens system comprising a negative and apositive spherical member of equal focal length positioned at a focallength distance from each other, and two equal negative cylindricalmembers having their axes at right angles, said cylindrical membersbeing movable relative to each other 7 and relative to the sphericalmembers longitudinally of the optical axis of the system and rotatableabout said optical axis.

5. An optical instrument having separate mountings for two lens systems,each comprising two negative lens elements and an intermediate positivelens element of equal focal lengths, one negative and the positive lenselement being mounted a focal length in distance from each other, meansfor moving the other negative lens element along the optical axis, saidmountings being pivoted at their anterior ends, rods telescopicallycarried by said mountings, an independent arm, a carriage mounted onsaid arm, said rods being pivoted to said carriage whereby the movementof said carriage secures a known angular convergence of said systems.

6. An optical instrument having separate mountings for two lens systems,each comprising two negative lens elements and an intermediate positivelens element of equal focal lengths, one negative and the positive lenselement being mounted a focal length in distance from each other, meansfor moving the other negative lens element along the optical axis, saidmountings being pivoted at their anterior ends, rods telescopi callycarried by said mountings, an independent arm, a carriage mounted onsaid arm, means for supporting a target upon said carriage, said rodsbeing pivoted to said carriage whereby the movement of said carriagesecures a known angular convergence of said systems.

7; In an optical instrument, a lens system comprising an intermediatepositive lens element, an ocular lens element located in the plane ofthe posterior principal focus of said positive element, and a negativeobjective lens element of the same focal length as the positive elementmovable along the optical axis of the system.

GEORGE A. ROGERS.

Witnesses:

HALLIE B. LEHMAN, BENJ. T. ROADHOUSE.

